Chaeles e



(No Model.)

0. E. SORIBNER.

GIRGUIT EOE DOUBLE STRANDED TELEPHONE SWITCH BOARD O0RDS'..

' No. 381,430. Patented Apr. 17, 1888.

\ III turn STATES ATE FICQ CHARLES E. SCRIBNER, OF CHICAGO, ILLINOIS,ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF SAME PLACE.

CIRCUIT FOR D OUBLBSTRANDED TELEPHONE-SWlTCH-BOARD CORDS.

SPECIFICATION forming part of Letters Patent No. 391,430, dated April17, 1888.

Application filed December 27, 1886. Renewed November fil, 1887. SerialNo. 255,768. (No model.)

To all whomit may concern.-

Be it known that I, CHARLES E. SURIBNER, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in Circuits forDouble-Stranded Telephone-Switch-Board Cords, (Case117,) of which thefollowing isa full, clear, concise, and exact description, referencebeing had to the accompanying drawings, forming a part of thisspecification.

My invention relates to the loop-plugs and doublestranded cords forconnecting metallic circuits of a telephone-exchange.

My invention may be used in telephone exchanges using single boards orin connection with multiple-switchboard systems. \Vhen one loop-plug ofapairisinserted in the springjack of a line, one portion of the line isconnected with the tip of the plug and the other portion with themetallic insulated sleeve upon the shank of the plug, and thus to thedifferent strands of the flexible cord.

The object of my invention is to provide a connection between thedifferent strands of the cord which will be closed when either plug ofthe pair is inserted in a spring-jack, so that the metallic circuit willbe completed through the strands.

My invention consists in providing a metallic heel for each of theloop-plugs of the different pairs and a metallic plate for each pair,upon which said heels normally rest in contact. This metallic plate ispermanently connected to the strand of the pair of cords with which thesleeves of the plugs of the pair are connected. In this manner I am ableto provide a circuit from one strand of the cord to the other, whichwill be closed when either plug is inserted in a spring-jack for thepurpose of answering the call of the subscriber.

My invention is illustrated in the accompanying drawings, in whichFigure 1 is a sectional view of the switch board, upon which are placedtwo spring-jacks for different telephone-lines, and a pair of loop-plugsand other key-board apparatus embodying my invention. Fig. 2 is a detailsectional view of the loop-plug, the metallic point being connected withthe heel and with one strand of the cord, and the insulated sleeve uponthe shank being connected with the other strand.

WVe will consider Fig. 2 as a detail of the plug a, insertedinspring-jack b. The insulated spring of switch I) is shown connectedwith the tip of the plug, while the frame of the switch is connectedwith the metallic sleeve. The spring and frame may be considered as theterminals of the different sides or branches of a single metalliccircuit. Thestrandc of the pair of cords connected with the tips oftheplugs or and (Z and the heel-piece of plug d is shown resting upon ametallic plate, 0. From this metallic plate 6 connection f is made tothe other strand, 9, of the pair of cords. Thus, when plug a is insertedin a switch, I), the circuit may be traced from the insulated spring ofsaid switch to the tip of plug a, thence by strand 0 through thetelephone and to the tip of plug (1, thence to the metallic plate 6, andthence by connection f to strand g, and by strand 9 back to the metallicsleeve of plug a, and thence to the frame of switch I), thus completingthe circuit between the terminals of the telephone line through theoperators telephone. A similar circuit will be formed when plug a restsupon plate 6 and plug dis inserted in a spring-jack switch. \Vhen plug dis inserted in another spring-jack, as spring-jack h, it is evident thatthe two metallic circuits will-be looped together through the strands ofthe cord, the branch f between plate 0 and strand g remaining open. Ithus provide a satisfactory connection between thetwo strands of a pairof cords when one of the plugs only is inserted in a spring-jack, andwhen the two plugs are inserted in different spring-jacks the metalliccircuits ofsaid spring-jacks will be looped together. It is evident thatthe circuit will be modified in different ways without departing from myinvention. For example, the heel of the plug may be connected with thesleeve instead of the tip, in which case the strand of the cordconnecting sleeve to sleeve of the plugs would include the telephone andthe branch f would connect with the strand connecting together the twotips.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In a switch-board apparatus, the combination, witha pair of loop-plugs and their pair of double-stranded cords, of ametallic plate, 6, in connection with one of said strands. and theheel-pieces of said plugs connected with the tips, respectively, wherebywhen one plug is inserted in a spring-jack the two strands will beconnected together, substantially as described.

2. The combination, with the two terminals of a spring-jack, b, of aloop-plug inserted therein, and the strands of a flexible cord andanother loop-plug, with its heel, which connects with its tip restingnpona metallic plate or connection, which is connected with a strand, 9,of the cords,'whereby circuit .is closed between the difierent terminalsof said springjack through the differentstrands of the cord,substantially as and for the purpose specified.

3. In a telephone-exchange switch-board apparatus, a pair of loop-plugsand their pair of double-stranded cords, one strand including thetelephone and the other strand being connected with a metallicconnection, with which the heel-piece of either of the plugs may beconnected, in combination with the two ter minals of a spring-jack, inwhich either of the plugs may be inserted, whereby the two terminals ofthe spring-j ack may be connected together through the differentstrands, substantially as described.

4. In a telephone switch-board, the combination of a double-strandedcord, two double terminal plugs, the two strands respectively connectedtogether, the two insulated portions of the plugs, metallic heels,-oneto each plug, each connected with one'of the terminalsofits plug andwith the same strand of the cord, a plate with which the heels oftheplugs may make contact, and a connection from said plate to thestrand of the cord which is not normally in connection with the heelsofthe plugs, whereby contact between the heelof a plug and the platesconnects together the two strands of the cord, while lifting the plugremoves that connection and leaves the branch connection to the plateopen. 1

5. The combination, with a spring -jack switch, of a loopplug insertedtherein, the spring of said switch being connected with the point of theplug, and the frame of the switch being connected with the metallicsleeve of the plug, the strands of a flexible cord connected withdifferent terminals of a corresponding plug, said plug being providedwith a metallic heel. connected with its sleeve, and a connection, f,from the metallic plate upon which said heel rests leading to the strand9, which connects the tips, whereby the two strands of the cord areconnected together, substantially as described.

In witness whereof I hereunto subscribe my name this 3d day of November,A. D. 1886.

CHARLES E. SGRIBNER.

Witnesses:

GEORGE P. BARTON, G. G. WOODWORTH.

